U.S. patent application number 12/308860 was filed with the patent office on 2009-09-17 for drive device for vehicle.
Invention is credited to Takeshi Mogari, Hiroki Sawada, Takaya Soma, Hiroshi Yoshida.
Application Number | 20090230908 12/308860 |
Document ID | / |
Family ID | 38997075 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090230908 |
Kind Code |
A1 |
Soma; Takaya ; et
al. |
September 17, 2009 |
Drive Device for Vehicle
Abstract
An object of the present invention is to suppress reverse of a
vehicle on an up-hill road against an intention of a driver. A
drive device for a vehicle according to the present invention
includes: an estimator for estimating whether or not reverse of the
vehicle occurs on an up-hill road; a rotating electric machine for
generating electric power by rotation of a drive wheel in the
vehicle when the vehicle reverses; a capacitor for electrically
charging the electric power generated by the rotating electric
machine; and a battery connected in parallel to the capacitor,
wherein the estimator estimates that the reverse of the vehicle
occurs when a current traveling road is an up-hill road and a
vehicular speed is smaller than a threshold whereas the electric
power of the capacitor is electrically discharged to the battery
when the reverse of the vehicle is estimated and the amount of
electric energy of the capacitor is greater than a certain
threshold.
Inventors: |
Soma; Takaya; (Toyota-shi,
JP) ; Yoshida; Hiroshi; (Anjo-shi, JP) ;
Mogari; Takeshi; (Nagoya-shi, JP) ; Sawada;
Hiroki; (Toyota-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Family ID: |
38997075 |
Appl. No.: |
12/308860 |
Filed: |
July 5, 2007 |
PCT Filed: |
July 5, 2007 |
PCT NO: |
PCT/JP2007/063874 |
371 Date: |
December 24, 2008 |
Current U.S.
Class: |
318/452 ;
180/65.265; 320/104 |
Current CPC
Class: |
B60L 50/16 20190201;
B60W 30/18118 20130101; B60W 2510/244 20130101; Y02T 10/7077
20130101; Y02T 10/7291 20130101; B60W 10/26 20130101; B60Y 2400/114
20130101; Y02T 10/7022 20130101; B60K 6/28 20130101; B60L 2240/642
20130101; B60W 2520/10 20130101; Y02T 10/6217 20130101; B60L 50/40
20190201; B60W 20/13 20160101; Y02T 10/6239 20130101; Y02T 10/6278
20130101; Y02T 10/7005 20130101; Y02T 10/62 20130101; Y02T 10/72
20130101; B60L 50/61 20190201; B60W 10/08 20130101; Y02T 90/16
20130101; B60W 20/00 20130101; B60K 6/365 20130101; B60L 3/0046
20130101; B60L 58/12 20190201; B60W 2540/12 20130101; Y02T 10/7072
20130101; F16H 2037/0866 20130101; Y02T 10/7241 20130101; B60L
2210/40 20130101; Y02T 10/70 20130101; B60K 1/02 20130101; B60L
2270/20 20130101; B60K 6/445 20130101; B60W 2552/15 20200201 |
Class at
Publication: |
318/452 ;
320/104; 180/65.265 |
International
Class: |
H02P 31/00 20060101
H02P031/00; H02J 7/00 20060101 H02J007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2006 |
JP |
2006-208276 |
Claims
1. A drive device for a vehicle, comprising: a drive shaft
connected to a drive wheel of a vehicle; a rotating electric
machine for traveling said vehicle, connected to said drive shaft,
for generating electric power with rotation of said drive shaft
when a reverse of said vehicle occurs on an up-hill road against an
intention of a driver; a capacitor connected to said rotating
electric machine, for electrically charging electric power
generated by said rotating electric machine; and a control unit for
controlling electric equipment including said rotating electric
machine and said capacitor; wherein said control unit estimates
whether or not said reverse occurs, and electrically discharges
electric power electrically charged to said capacitor when an
occurrence of said reverse is estimated.
2. The drive device for a vehicle according to claim 1, wherein
said control unit calculates an amount of electric energy
electrically charged to said capacitor, and electrically discharges
said electric power until said calculated amount of electric energy
becomes a predetermined value or lower.
3. The drive device for a vehicle according to claim 1, further
comprising a secondary battery connected to said rotating electric
machine in parallel to said capacitor; wherein said control unit
electrically discharges the electric power of said capacitor in
such a manner as to electrically charge said secondary battery.
4. The drive device for a vehicle according to claim 1, wherein
said rotating electric machine includes a first rotating electric
machine and a second rotating electric machine connected to said
drive shaft, said drive device further comprises a gear mechanism
including a first gear connected to said drive shaft, a second gear
meshing with said first gear and being connected to an output shaft
of an internal combustion engine for said vehicle, and a third gear
meshing with said first gear via said second gear and being
connected to a rotation shaft of said first rotating electric
machine.
5. A drive device for a vehicle, comprising: an engine; a first
rotating electric machine; a drive shaft connected to a drive
wheel; a distributing mechanism connected to said engine, said
first rotating electric machine and said drive shaft, for
distributing power from said engine to said first rotating electric
machine and said drive shaft; a second rotating electric machine
connected to said drive shaft; a first inverter connected to said
first rotating electric machine, for converting and outputting
electric power; a second inverter connected to said second rotating
electric machine, for converting and outputting electric power; a
converter connected to said first inverter and said second
inverter, for transforming and outputting a voltage; a secondary
battery connected to said converter; a capacitor connected to said
first inverter and said second inverter in parallel to said
converter; and a control unit for controlling electric equipment
including said first inverter, said second inverter and said
converter; wherein said control unit estimates whether or not a
reverse of said vehicle occurs on an up-hill road against an
intention of a driver, and controls said converter in such a manner
as to step down a voltage input from said capacitor to output the
voltage to said secondary battery when an occurrence of said
reverse is estimated.
6. The drive device for a vehicle according to claim 5, further
comprising a voltmeter for detecting a voltage at said capacitor,
wherein said control unit calculates an amount of electric energy
electrically charged to said capacitor based on the voltage at said
capacitor, and controls said converter by stepping down a voltage
input from said capacitor to output the voltage to said secondary
battery until the amount of electric energy electrically charged to
said capacitor becomes a predetermined value or lower when the
occurrence of said reverse is estimated.
7. The drive device for a vehicle according to claim 1, wherein
said control unit estimates whether or not said reverse occurs
based on a gradient of said up-hill road, a brake pedaling force
and a vehicular speed.
8. A drive device for a vehicle, comprising: a drive shaft
connected to a drive wheel of a vehicle; a rotating electric
machine for traveling said vehicle, connected to said drive shaft,
for generating electric power with rotation of said drive shaft
when a reverse of said vehicle occurs on an up-hill road against an
intention of a driver; a capacitor connected to said rotating
electric machine, for electrically charging electric power
generated by said rotating electric machine; and control means for
controlling electric equipment including said rotating electric
machine and said capacitor; wherein said control means includes:
estimating means for estimating whether or not said reverse occurs;
and electrically discharging means for electrically discharging the
electric power electrically charged to said capacitor when the
occurrence of said reverse is estimated.
9. The drive device for a vehicle according to claim 8, wherein
said control means further includes means for calculating the
amount of electric energy electrically charged to said capacitor;
and said electrically discharging means includes means for
electrically discharging said electric power until said calculated
amount of electric energy becomes a predetermined value or
lower.
10. The drive device for a vehicle according to claim 8, further
comprising a secondary battery connected to said rotating electric
machine in parallel to said capacitor; wherein said electrically
discharging means includes means for electrically discharging the
electric power of said capacitor in such a manner as to
electrically charge said secondary battery.
11. The drive device for a vehicle according to claim 8, wherein
said rotating electric machine includes a first rotating electric
machine and a second rotating electric machine connected to said
drive shaft, said drive device further comprises a gear mechanism
including a first gear connected to said drive shaft, a second gear
meshing with said first gear and being connected to an output shaft
of an internal combustion engine for said vehicle, and a third gear
meshing with said first gear via said second gear and being
connected to a rotation shaft of said first rotating electric
machine.
12. A drive device for a vehicle, comprising: an engine; a first
rotating electric machine; a drive shaft connected to a drive
wheel; a distributing mechanism connected to said engine, said
first rotating electric machine and said drive shaft, for
distributing power from said engine to said first rotating electric
machine and said drive shaft; a second rotating electric machine
connected to said drive shaft; a first inverter connected to said
first rotating electric machine, for converting and outputting
electric power; a second inverter connected to said second rotating
electric machine, for converting and outputting electric power; a
converter connected to said first inverter and said second
inverter, for transforming and outputting a voltage; a secondary
battery connected to said converter; a capacitor connected to said
first inverter and said second inverter in parallel to said
converter; and a control unit for controlling electric equipment
including said first inverter, said second inverter and said
converter; wherein said control unit includes: estimating means for
estimating whether or not a reverse of said vehicle occurs on an
up-hill road against an intention of a driver; and converter
controlling means for controlling said converter by stepping down a
voltage input from said capacitor to output the voltage to said
secondary battery when the occurrence of said reverse is
estimated.
13. The drive device for a vehicle according to claim 12, further
comprising a voltmeter for detecting the voltage at said capacitor,
wherein said control unit further includes means for calculating an
amount of electric energy electrically charged to said capacitor
based on the voltage at said capacitor; and said converter
controlling means includes means for controlling said converter by
stepping down a voltage input from said capacitor to output the
voltage to said secondary battery until the amount of electric
energy electrically charged to said capacitor becomes a
predetermined value or lower when the occurrence of said reverse is
estimated.
14. The drive device for a vehicle according to claim 8, wherein
said estimating means includes means for estimating whether or not
said reverse occurs based on a gradient of said up-hill road, a
brake pedaling force and a vehicular speed.
Description
TECHNICAL FIELD
[0001] The present invention relates to a drive device for a
vehicle provided with a rotating electric machine for traveling
and, more particularly, to a technique for electrically charging a
capacitor with electric power generated by a rotary electric
machine.
BACKGROUND ART
[0002] Attention has been recently directed to a hybrid vehicle
which travels by drive force from at least either one of an engine
and a motor as part of measures for environmental issues. On such a
hybrid vehicle is mounted a capacitor (i.e., a condenser) or the
like for accumulating electric power to be supplied to the motor.
Japanese Patent Laying-Open No. 2005-061498 discloses a hybrid
vehicle having such a battery or such a capacitor mounted
thereon.
[0003] The hybrid vehicle disclosed in Japanese Patent Laying-Open
No. 2005-061498 includes: an engine; a first motor generator for
exhibiting both of a function of an electric motor and a function
of a power generator, a power distributing mechanism for
distributing power of the engine to the first motor generator and a
transmission shaft; a second motor generator connected to the
transmission shaft, to exhibit both of the function of the electric
motor and the function of the power generator; a transmission
connected to the transmission shaft, to change and output the
rotational speed of the transmission shaft; a drive shaft connected
to an output shaft of the transmission via a differential; a drive
wheel connected to the drive shaft; and a battery and a capacitor
electrically connected to the first motor generator and the second
motor generator via inverters, respectively.
[0004] In the hybrid vehicle disclosed in Japanese Patent
Laying-Open No. 2005-061498, electric power accumulated in the
battery and the capacitor is electrically discharged to the first
motor generator and the second motor generator at the time of the
start of the vehicle. In the meantime, regenerative electric power
generated in the first motor generator and the second motor
generator is electrically charged to the battery and the capacitor
at the time of deceleration of the vehicle. The capacitor excellent
in input/output characteristics more than the battery is used in a
case where a large current is instantaneously generated during the
electric charging/discharging. As a consequence, it is possible to
suppress any up-sizing of the battery.
[0005] On the other hand, when a driver drives forward a vehicle at
a standstill on an up-hill road by switching from a brake pedal to
an acceleration pedal, the vehicle may be unexpectedly moved
backward against an intention of the driver (such a phenomenon is
referred to also "slip-down," but hereinafter simply referred to
"reverse"). As soon as the vehicle is started to be reversed, the
drive wheels also are started to be rotated in a direction of the
reverse of the vehicle. The rotation of the drive wheels is
transmitted to the first motor generator and the second motor
generator via the drive shaft and the transmission, to thus
generate electric power. The generation of the electric power
produces torque for suppressing the rotation of the drive wheels
(i.e., the reverse of the vehicle). In order to further increase
the suppressing torque, it is necessary to efficiently consume the
generated electric power at the time of the reverse. In the hybrid
vehicle disclosed in Japanese Patent Laying-Open No. 2005-061498,
the generated electric power at the time of the reverse can be
electrically charged to the battery and the capacitor, and
therefore, a greater suppressing torque can be expected in
comparison with a case of the electric charging only to the
battery.
[0006] However, in the hybrid vehicle disclosed in Japanese Patent
Laying-Open No. 2005-061498, the generated electric power at the
time of the reverse is electrically charged only to the battery
when the capacitor is in a fully electrically charged state at the
time of the reverse. Therefore, the smaller suppressing torque
makes it difficult to suppress the reverse of the vehicle in
comparison with a case of the electric discharging to both of the
battery and the capacitor.
DISCLOSURE OF THE INVENTION
[0007] The present invention has been accomplished to solve the
above-described problems. Therefore, an object of the present
invention is to provide a drive device for a vehicle, in which the
vehicle can be suppressed from reversing against an intention of a
driver on an up-hill road.
[0008] A drive device for a vehicle according to the present
invention includes: a drive shaft connected to a drive wheel of a
vehicle; a rotating electric machine for traveling the vehicle,
connected to the drive shaft, for generating electric power with
rotation of the drive shaft when a reverse of the vehicle occurs on
an up-hill road against an intention of a driver; a capacitor
connected to the rotating electric machine, for electrically
charging electric power generated by the rotating electric machine;
and a control unit for controlling electric equipment including the
rotating electric machine and the capacitor. The control unit
estimates whether or not the reverse occurs, and electrically
discharges electric power electrically charged to the capacitor
when the occurrence of the reverse is estimated.
[0009] According to the above-described aspect, the drive wheel is
started to be rotated backward of the vehicle when the vehicle
reverses on the up-hill road against an intention of the driver.
The drive shaft is rotated in association with the rotation of the
drive wheel, and therefore, the rotating electric machine for
allowing the vehicle to travel generates the electric power. The
generation of the electric power generates torque for suppressing
the rotation of the drive shaft, thereby suppressing the reverse of
the vehicle. If the capacitor to be electrically charged by the
electric power generated by the rotating electric machine is in a
fully electrically charged state at the time of the reverse, power
generation by the rotating electric machine is suppressed, and
therefore, it is difficult to suppress the rotation of the drive
shaft. In view of this, it is estimated whether or not the reverse
occurs. If the occurrence of the reverse is estimated, the electric
power electrically charged to the capacitor is electrically
discharged. As a consequence, the capacitor comes into an
electrically chargeable state before the reverse, and then, the
capacitor can electrically charge a large electric power at the
time of the reverse. In this manner, it is possible to increase the
electric power generated by the rotating electric machine so as to
increase the torque for suppressing the rotation of the drive shaft
at the time of the reverse. Consequently, there can be provided the
drive device capable of suppressing the reverse of the vehicle on
the up-hill road against an intention of the driver.
[0010] Preferably, the control unit should calculate the amount of
electric energy electrically charged to the capacitor, and should
electrically discharge the electric power until the calculated
amount of electric energy becomes a predetermined value or
lower.
[0011] According to the above-described aspect, the amount of
electric energy electrically charged to the capacitor is
calculated. If the occurrence of the reverse is estimated, the
electric power electrically charged to the capacitor is
electrically discharged until the calculated amount of electric
energy becomes the predetermined value or lower. Thus, the
capacitor can electrically charge the large electric power at the
time of the reverse by decreasing the amount of electric energy
electrically charged to the capacitor before the reverse.
[0012] More preferably, the drive device should further include a
secondary battery connected to the rotating electric machine in
parallel to the capacitor. The control unit should electrically
discharge the electric power of the capacitor in such a manner as
to electrically charge the secondary battery.
[0013] According to the above-described aspect, the electric power
electrically discharged by the capacitor at the time of the reverse
is electrically charged to the secondary battery. As a consequence,
it is possible to turn the capacitor into an electrically
chargeable state by decreasing the electric power electrically
charged to the capacitor without any waste of the electric power.
Moreover, the secondary battery is connected to the rotating
electric machine in parallel to the capacitor. Consequently, the
electric power generated by the rotating electric machine at the
time of the reverse can be electrically charged to the secondary
battery in addition to the capacitor. In this manner, it is
possible to further increase the electric power generated by the
rotating electric machine at the time of the reverse, so as to
further increase the torque for suppressing the rotation of the
drive shaft.
[0014] Still more preferably, the rotating electric machine should
include a first rotating electric machine and a second rotating
electric machine connected to the drive shaft. The drive device
should further include a gear mechanism provided with a first gear
connected to the drive shaft, a second gear meshing with the first
gear and being connected to an output shaft of an internal
combustion engine for the vehicle, and a third gear meshing with
the first gear via the second gear and being connected to a
rotation shaft of the first rotating electric machine.
[0015] According to the above-described aspect, the rotation of the
drive shaft at the time of the reverse allows the second rotating
electric machine to be rotated. Furthermore, the rotation of the
drive shaft is transmitted to the first gear, the second gear and
the third gear, thereby rotating the first rotating electric
machine. As a consequence, the first rotating electric machine also
generates the electric power in addition to the second rotating
electric machine. Therefore, it is possible to further increase the
torque for suppressing the rotation of the drive shaft in
comparison with a case where the electric power is generated by a
single rotating electric machine.
[0016] A drive device for a vehicle according to another aspect of
the present invention includes: an engine; a first rotating
electric machine; a drive shaft connected to a drive wheel; a
distributing mechanism connected to the engine, the first rotating
electric machine and the drive shaft, for distributing power from
the engine to the first rotating electric machine and the drive
shaft; a second rotating electric machine connected to the drive
shaft; a first inverter connected to the first rotating electric
machine, for converting and outputting the electric power; a second
inverter connected to the second rotating electric machine, for
converting and outputting the electric power; a converter connected
to the first inverter and the second inverter, for transforming and
outputting a voltage; a secondary battery connected to the
converter; a capacitor connected to the first inverter and the
second inverter in parallel to the converter; and a control unit
for controlling electric equipment including the first inverter,
the second inverter and the converter. The control unit estimates
whether or not a reverse of the vehicle occurs on an up-hill road
against an intention of a driver, and controls the converter in
such a manner as to step down a voltage input from the capacitor to
output the voltage to the secondary battery when the occurrence of
the reverse is estimated.
[0017] According to the above-described aspect, the drive wheel is
started to be rotated backward of the vehicle when the vehicle
reverses on the up-hill road against an intention of the driver.
The drive shaft is rotated in association with the rotation of the
drive wheel, and therefore, the second rotating electric machine
connected to the drive shaft and the first rotating electric
machine connected to the drive shaft via the distributing mechanism
generates AC electric power. The generation of the electric power
generates torque for suppressing the rotation of the drive shaft,
thereby suppressing the reverse of the vehicle. The AC electric
power generated by the first rotating electric machine and the
second rotating electric machine is converted into DC electric
power by the first inverter and the second inverter, respectively.
The converted DC electric power is electrically charged to the
capacitor, and further, the voltage is stepped down by the
converter, to be electrically charged to the secondary battery. If
the capacitor is in a fully electrically charged state at the time
of the reverse, the converted DC electric power cannot be
electrically charged to only the secondary battery. In view of
this, the power generation by the first rotating electric machine
and the second rotating electric machine is suppressed, and
therefore, it is difficult to suppress the rotation of the drive
shaft. In view of this, it is estimated whether or not the reverse
occurs. If the occurrence of the reverse is estimated, the
converter is controlled in such a manner as to step down the
voltage input from the side of the capacitor, and then, to output
it onto the side of the secondary battery. In this manner, the
electric power at the capacitor is electrically discharged, and
thus, the secondary battery is electrically charged. As a
consequence, it is possible to turn the capacitor into an
electrically chargeable state by decreasing the electric power
electrically charged to the capacitor without any waste of the
electric power before the reverse. Thus, the capacitor can
electrically charge a large electric power at the time of the
reverse. At the time of the reverse, it is possible to increase the
electric power generated by the first rotating electric machine and
the second rotating electric machine, so as to increase the torque
for suppressing the rotation of the drive shaft. Consequently,
there can be provided the drive device capable of suppressing the
reverse of the vehicle on the up-hill road against an intention of
the driver.
[0018] Preferably, the drive device should further include a
voltmeter for detecting the voltage at the capacitor. The control
unit should calculate the amount of electric energy electrically
charged to the capacitor based on the voltage at the capacitor, and
should control the converter by stepping down a voltage input from
the capacitor to output the voltage to the secondary battery until
the amount of electric energy electrically charged to the capacitor
becomes a predetermined value or lower when the occurrence of the
reverse is estimated.
[0019] According to the above-described aspect, the amount of
electric energy electrically charged to the capacitor is calculated
based on the voltage of the capacitor. If the occurrence of the
reverse is estimated, the converter is controlled in such a manner
as to step down the voltage to be input from the side of the
capacitor, to output it onto the side of the secondary battery
until the calculated amount of electric energy becomes the
predetermined value or lower. Thus, the capacitor can electrically
charge the large electric power at the time of the reverse by
decreasing the amount of electric energy electrically charged to
the capacitor before the reverse.
[0020] Still more preferably, the control unit should estimate
whether or not the reverse occurs based on a gradient of the
up-hill road, a brake pedaling force and a vehicular speed.
[0021] According to the above-described aspect, it is estimated
whether or not the reverse occurs based on the gradient of the
up-hill road, the brake pedaling. force and the vehicular speed.
For example, it is estimated that the reverse occurs when the
vehicular speed is almost zero upon request for braking by the
driver on the up-hill road whose gradient is greater than a
predetermined value. Thus, it is possible to accurately estimate
the occurrence of the reverse.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a diagram illustrating a structure of a vehicle
having a drive device mounted thereon in an embodiment according to
the present invention.
[0023] FIG. 2 is a diagram illustrating a power split device for
the vehicle having the drive device mounted thereon in the
embodiment according to the present invention.
[0024] FIG. 3 is a collinear chart illustrating the
interrelationship among rotational speeds of an engine, an MG (1)
and an MG (2) in the vehicle having the drive device mounted
thereon in the embodiment according to the present invention.
[0025] FIG. 4 is a functional block diagram illustrating the drive
device in the embodiment according to the present invention.
[0026] FIG. 5 is a flowchart illustrating a control structure of an
ECU constituting the drive device in the embodiment according to
the present invention.
[0027] FIG. 6 is a chart illustrating the interrelationship among
rotational speeds of the engine, the MG (1) and the MG (2) and
torque acting on the vehicle in the vehicle having the drive device
mounted thereon in the embodiment according to the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0028] Referring to the attached drawings, description will be made
below on an embodiment according to the present invention. In the
following description, the same component parts are designated by
the same reference numerals whose names and functions are the same.
Therefore, detailed description thereof will not be repeated
below.
First Embodiment
[0029] Referring to FIG. 1, description will be given below of a
hybrid vehicle having a drive device mounted thereon in the present
embodiment. The vehicle includes: an engine 100, an MG
(abbreviating "a motor generator") (1) 200, an MG (2) 300, a power
split device 400, an inverter (1) 500, an inverter (2) 600, a
battery 700, a converter 800, a capacitor 900, a speed reducer
2100, a drive shaft 2200 and drive wheels 2300. The vehicle travels
with drive force from at least either one of engine 100 and MG (2)
300.
[0030] Engine 100, MG (1) 200 and MG (2) 300 are connected to each
other via power split device 400. Power generated by engine 100 is
split into two channels by power split device 400. On one of the
channels, drive wheels 2300 are driven via speed reducer 2100 and
drive shaft 2200. On the other channel, MG (1) 200 is driven,
thereby generating electric power.
[0031] MG (1) 200 is a three-phase AC motor. MG (1) 200 generates
the electric power by the power of engine 100, split by power split
device 400. Here, the use of the electric power generated by MG (1)
200 is varied according to a traveling condition of the vehicle or
an SOC (abbreviating a "state of change") of battery 700. The
electric power generated by MG (1) 200 is used as electric power
for driving MG (2) 300 as it is, for example, during normal
traveling. In contrast, when the SOC of battery 700 is lower than a
predetermined value, the electric power generated by MG (1) 200 is
converted from an AC to a DC by inverter (1) 500. Thereafter, a
voltage is regulated by converter 800, to be then accumulated in
battery 700: otherwise, no voltage is regulated, to be then
accumulated in capacitor 900.
[0032] MG (2) 300 is a three-phase AC motor. MG (2) 300 is driven
by at least any one of the electric power accumulated in battery
700, the electric power accumulated in capacitor 900 and the
electric power generated by MG (1) 200. To MG (2) 300 is supplied
electric power converted from a DC to an AC by inverter (2)
600.
[0033] The drive force of MG (2) 300 is transmitted to drive wheels
2300 via speed reducer 2100 and drive shaft 2200. As a consequence,
MG (2) 300 assists engine 100 or allows the vehicle to travel by
its drive force.
[0034] In the meantime, MG (2) 300 is driven by drive wheels 2300
via speed reducer 2100 during regenerative braking of the hybrid
vehicle, to be thus actuated as a power generator. In this way, MG
(2) 300 acts as a regenerative brake for converting braking energy
into electric power. The electric power generated by MG (2) 300 is
accumulated in battery 700 or capacitor 900 via inverter (2)
600.
[0035] Battery 700 is a combined battery constituted by connecting,
in series, a plurality of battery modules having a plurality of
battery cells integrated with each other. A discharging voltage and
a charging voltage from and to battery 700 are regulated by
converter 800.
[0036] A smoothing capacitor 720 is connected in parallel to
inverter (1) 500 and inverter (2) 600. Smoothing capacitor 720
temporarily accumulates electric charges therein in order to smooth
the electric power supplied from battery 700 or the electric power
supplied from inverter (1) 500 or inverter (2) 600. The smoothed
electric power is supplied to inverter (1) 500, inverter (2) 600 or
battery 700.
[0037] A system main relay 710 is constituted of an SMR (1) 712 and
an SMR (2) 716 on a positive electrode side and an SMR (3) 718 on a
negative electrode side. SMR (1) 712, SMR (2) 716 and SMR (3) 718
are relays for closing a contact which is turned on upon
energization of an excitation current with respect to a coil. SMR
(1) 712 and SMR (2) 716 are disposed on the positive electrode
side. Moreover, SMR (1) 712 and SMR (2) 716 are connected in
parallel to each other. To SMR (1) 712 is connected a limitation
resistor 714 in series. In order to prevent any inrush current from
flowing in inverter (1) 500 or inverter (2) 600, SMR (1) 712 is
connected before the connection of SMR (2) 716, thereby
pre-charging smoothing capacitor 720. SMR (2) 716 is an SMR on the
positive side, connected after the connection of SMR (1) 712 and
the completion of the pre-charging. SMR (3) 718 is an SMR on the
negative side, disposed on the negative electrode side of battery
700. Each of the SMRs is controlled by an ECU (abbreviating "an
electronic control unit") 1000.
[0038] During the turning-on of a power source (i.e., when a
position of an ignition switch is changed over from an OFF position
to an STA position), ECU 1000 first turns on SMR (3) 718, and then,
turns on SMR (1) 712, thereby carrying out the pre-charging of
smoothing capacitor 720. Since limitation resistor 714 is connected
to SMR (1) 712, a voltage applied to smoothing capacitor 720 is
moderately increased even if SMR (1) 712 is turned on, thereby
preventing any generation of an inrush current in inverter (1) 500
or inverter (2) 600. After the pre-charging is carried out, ECU
1000 turns on SMR (2) 716.
[0039] In contrast, during the turning-off of the power source
(i.e., when the position of the ignition switch is changed over
from the STA position to the OFF position), ECU 1000 turns off SMR
(1) 712, SMR (2) 716 and SMR (3) 718, so as to prevent any leakage
of the current from battery 700.
[0040] Capacitor 900 is constituted by connecting a plurality of
cells in parallel to each other. Here, capacitor 900 may be
constituted by connecting some cells in series in order to enhance
withstand voltage performance.
[0041] ECU 1000 controls engine 100, inverter (1) 500, inverter (2)
600 and converter 800. ECU 1000 includes an HV (abbreviating "a
hybrid vehicle") _ECU 1100, an MG_ECU 1200 and an engine ECU
1300.
[0042] Into HV_ECU 1100 are input a signal representing a
temperature of capacitor 900 from a temperature sensor 902 and a
signal representing a voltage of capacitor 900 from a capacitor
voltmeter 904. Furthermore, into HV_ECU 1100 are input a signal
representing a gradient G of a traveling road from a G sensor 2010,
a signal representing a brake pedaling force from a brake pedaling
force sensor 2020 and a signal representing a vehicular speed V
from a vehicular speed sensor 2030, respectively.
[0043] In addition, HV_ECU 1100 is connected to a base plate 910,
to which terminals of the capacitor cells are grounded, thereby
detecting a voltage of each of the capacitor cells via the base
plate 910. Here, a voltmeter may be disposed in each of the
capacitor cells in place of the detection of the voltage of each of
the capacitor cells by the use of the base plate 910.
[0044] HV_ECU 1100 calculates an electrically charging/discharging
power to battery 700 and capacitor 900 based on vehicular speed V,
an accelerator pedal position or the brake pedaling force.
Additionally, HV_ECU 1100 calculates an electrically charging power
limit value (a maximum value of electric power to be electrically
charged) WIN(B) and an electrically discharging power limit value
(a maximum value of electric power to be electrically discharged)
WOUT(B) to battery 700 based on the temperature of battery 700 or
the SOC.
[0045] In the same manner, HV_ECU 1100 calculates an electrically
charging power limit value WIN(C) and an electrically discharging
power limit value WOUT(C) to capacitor 900 based on the temperature
or voltage of capacitor 900.
[0046] Into MG_ECU 1200 are input a signal representing the
rotational speed of MG (1) 200 from a rotational speed sensor 202
and a signal representing the rotational speed of MG (2) 300 from a
rotational speed sensor 302. Into engine ECU 1300 is input a signal
representing the rotational speed of engine 100 from a rotational
speed sensor 102.
[0047] HV_ECU 1100, MG_ECU 1200 and engine ECU 1300 are connected
to each other in such a manner as to freely transmit and receive
the signals to and from each other. HV_ECU 1100 calculates request
output values to engine 100, MG (1) 200 and MG (2) 300 based on the
signals input into the ECUs or a program and a map stored in a
memory (not shown). At this time, HV_ECU 1100 calculates the
request output values to MG (1) 200 and MG (2) 300 such that the
sum of values of the electric power generated by MG (1) 200 and MG
(2) 300 never exceeds the sum of electrically charging power limit
value WIN(B) and electrically charging power limit value
WIN(C).
[0048] MG_ECU 1200 controls inverter (1) 500 and inverter (2) 600
based on the request output values to MG (1) 200 and MG (2) 300,
thereby controlling MG (1) 200 and MG (2) 300.
[0049] Engine ECU 1300 controls engine 100 based on the request
output value to engine 100.
[0050] In the present embodiment, the electrically
charging/discharging of battery 700 and the electrically
charging/discharging of capacitor 900 are controlled by changing an
output voltage (i.e., a system voltage) of converter 800.
[0051] For example, in a case where the electric power is supplied
to MG (1) 200 or MG (2) 300, capacitor 900 is electrically
discharged by priority by setting the output voltage of converter
800 lower than the voltage of capacitor 900. In contrast, battery
700 is electrically discharged by priority by setting the output
voltage of converter 800 higher than the voltage of capacitor
900.
[0052] On the other hand, in a case where the electric power
generated by MG (1) 200 or MG (2) 300 is electrically charged to
battery 700 or capacitor 900, battery 700 is electrically charged
by priority by setting the output voltage of converter 800 lower
than the voltage of capacitor 900. In contrast, capacitor 900 is
electrically charged by priority by setting the output voltage of
converter 800 higher than the voltage of capacitor 900.
[0053] Moreover, HV_ECU 1100 controls converter 800, and then,
distributes the electric power generated by MG (1) 200 or MG (2)
300 to capacitor 900 and battery 700 in such a manner that an
electric charging power value P(C) of capacitor 900 and an electric
charging power value P(B) of battery 700 never exceed their
limitation values. Consequently, capacitor 900 and battery 700 can
be suppressed from being turned to overcurrent and overvoltage
states.
[0054] With reference to FIG. 2, description will be further made
on power split device 400. Power split device 400 is constituted of
a planetary gear including a sun gear 402, a pinion gear 404, a
carrier 406 and a ring gear 408.
[0055] Pinion gear 404 meshes with sun gear 402 and ring gear 408.
Carrier 406 rotatably supports pinion gear 404. Sun gear 402 is
connected to a rotation shaft of MG (1) 200. Carrier 406 is
connected to a crankshaft of engine 100. Ring gear 408 is connected
to a rotation shaft of MG (2) 300 and speed reducer 2100.
[0056] Since engine 100, MG (1) 200 and MG (2) 300 are connected to
each other via power split device 400 constituted of the planetary
gear, the rotational speeds of engine 100, MG (1) 200 and MG (2)
300 have an interrelationship of connection on a straight line in a
collinear chart, as illustrated in FIG. 3.
[0057] When the vehicle reverses on an up-hill road against an
intention of a driver in the present embodiment, drive wheels 2300
are started to be rotated in a vehicle reverse direction. The
rotation of drive wheels 2300 is transmitted to MG (2) 300 via
drive shaft 2200 and speed reducer 2100. In addition, the rotation
of drive wheels 2300 is transmitted to MG (1) 200 via ring gear
408, pinion gear 404 and sun gear 402. In this manner, MG (1) 200
and MG (2) 300 generate the electric power owing to the rotation.
This power generation allows torque for suppressing the reverse of
the vehicle (i.e., a reverse suppressing torque) to be
generated.
[0058] Referring to FIG. 4, description will be made on a function
of suppressing the reverse of the vehicle by HV_ECU 1100
constituting the drive device in the present embodiment.
[0059] HV_ECU 1100 includes an up-hill road determiner 1110, a
brake determiner 1120, a vehicular speed determiner 1130, a reverse
estimator 1140, a capacitor electric energy calculator 1150, a
capacitor electric discharge determiner 1160 and a control signal
transmitter 1170.
[0060] Up-hill road determiner 1110 detects gradient G in response
to the signal from G sensor 2010, thereby determining whether or
not a current traveling road is an up-hill road.
[0061] Brake determiner 1120 detects the brake pedaling force in
response to the signal from brake pedaling force sensor 2020,
thereby determining whether or not a brake is turned on.
[0062] Vehicular speed determiner 1130 detects vehicular speed V in
response to the signal from vehicular speed sensor 2030, thereby
determining whether or not vehicular speed V is lower than a
predetermined threshold V (0).
[0063] Reverse estimator 1140 estimates the reverse of the vehicle
which may occur within a reasonably short period of time based on
the determination results of up-hill road determiner 1110, brake
determiner 1120 and vehicular speed determiner 1130.
[0064] Capacitor electric energy calculator 1150 detects a
capacitor voltage in response to the signal from capacitor
voltmeter 904, thereby calculating amount Q of electric energy
electrically charged to capacitor 900.
[0065] Capacitor electric discharge determiner 1160 determines
whether or not the electric discharging is performed from capacitor
900 to battery 700 based on amount Q of electric energy calculated
by capacitor electric energy calculator 1150 when reverse estimator
1140 estimates the reverse of the vehicle.
[0066] Control signal transmitter 1170 transmits, to converter 800,
a control signal which allows the voltage on the side of capacitor
900 to be stepped down to a rated voltage of battery 700, so as to
output it toward battery 700 when capacitor electric discharge
determiner 1160 determines that the electric discharging is
performed from capacitor 900 to battery 700. Thus, the electric
power electrically charged to capacitor 900 is supplied to battery
700.
[0067] In the present embodiment, these functions are implemented
in accordance with the program to be executed by HV_ECU 1100 (this
program may be recorded on a recording medium, and then, may be
distributed in a market). Incidentally, these functions may be
constituted of not the program (i.e., software) but hardware.
[0068] With reference to FIG. 5, description will be given of a
control structure of the program implemented by HV_ECU 1100
constituting the drive device in the present embodiment when the
reverse of the vehicle is suppressed.
[0069] In step (a step will be hereinafter abbreviated as "S") 100,
HV_ECU 1100 detects gradient G in response to the signal from G
sensor 2010.
[0070] In S102, HV_ECU 1 100 determines based on gradient G whether
or not the current traveling road is the up-hill road. HV_ECU 1100
determines that the current traveling road is the up-hill road in a
case of, for example, the signal representing that gradient G is
higher than the predetermined threshold. If the current traveling
road is the up-hill road (YES in S102), the processing proceeds to
S104. In contrast, if otherwise (NO in S102), the processing
returns to S100.
[0071] In S104, HV_ECU 1100 detects the brake pedaling force in
response to the signal from brake pedaling force sensor 2020.
[0072] In S106, HV_ECU 1100 determines based on the brake pedaling
force whether or not the brake is turned on. HV_ECU 1100 determines
that the brake is turned on in a case where the brake pedaling
force is higher than the predetermined threshold. If the brake is
turned on (YES in S106), the processing proceeds to S108. In
contrast, if otherwise (NO in S106), the processing returns to
S100.
[0073] In S108, HV_ECU 1100 detects vehicular speed V in response
to the signal from vehicular speed sensor 2030.
[0074] In S110, HV_ECU 1100 determines whether or not vehicular
speed V is lower than predetermined threshold V (0). Threshold V
(0) is set to be substantially zero. When vehicular speed V is
lower than threshold V (0), the vehicle is in an almost standstill
state. If vehicular speed V is lower than threshold V (0) (YES in
S110), the processing proceeds to S112. In contrast, if otherwise
(NO in S110), the processing returns to S100.
[0075] In S112, HV_ECU 1100 estimates that the reverse of the
vehicle occurs within a reasonably short period of time.
[0076] In S114, HV_ECU 1100 detects the capacitor voltage in
response to the signal from capacitor voltmeter 904.
[0077] In S116, HV_ECU 1100 calculates amount Q of capacitor
electric energy based on the capacitor voltage. Here, HV_ECU 1100
calculates amount Q of capacitor electric energy based on the
amount of capacitor electric charges calculated based on the
capacitor voltage. Incidentally, the amount of capacitor electric
charges is calculated in accordance with an inequality of
C.times.(the square of the capacitor voltage)/2, where C designates
a capacitance of capacitor 900.
[0078] In S118, HV_ECU 1100 determines whether or not amount Q of
capacitor electric energy is lower than predetermined threshold Q
(0). Threshold Q (0) is set to be substantially zero, for example.
If amount Q of capacitor electric energy is lower than threshold Q
(0) (YES in S118), the processing comes to an end. In contrast, if
otherwise (NO in S118), the processing proceeds to S120.
[0079] In S120, HV_ECU 1100 transmits, to converter 800, a control
signal which allows the voltage on the side of capacitor 900 to be
stepped down to the rated voltage of battery 700, so as to output
it to battery 700 in such a manner that the electric discharging is
performed from capacitor 900 to battery 700.
[0080] With the above-described structure and based on the
above-described flowchart, description will be made on operation of
the drive device according to the present embodiment.
[0081] When the vehicle is started to reverse on the up-hill road
against an intention of the driver, MG (1) 200 and MG (2) 300
generate the electric power. As a consequence, the greater reverse
suppressing torque is generated in comparison with a case where the
electric power is generated by a single motor generator. In order
to further increase the reverse suppressing torque, MG (1) 200 and
MG (2) 300 need generate the larger electric power.
[0082] When capacitor 900 is in the fully electrically charged
state during the reverse, the electric power generated by MG (1)
200 and MG (2) 300 can be electrically charged only to battery 700,
thereby suppressing the power generation by MG (1) 200 and MG (2)
300. Therefore, the reverse suppressing torque becomes smaller, as
indicated by an alternate long and short dashed line in FIG. 6, so
that the vehicle reverses farther.
[0083] In view of the above, when the traveling road of the vehicle
is the up-hill road (YES in S102), the brake is turned on (YES in
S106) and the vehicle comes to an almost halt at vehicular speed V
of substantially zero (YES in S110), it is estimated that the
reverse of the vehicle occurs within a reasonably short period of
time (S112). In response to the signal from capacitor voltmeter 904
is detected the capacitor voltage (S114), and thereafter, based on
the capacitor voltage is calculated amount Q of capacitor electric
energy (S116). If amount Q of capacitor electric energy is higher
than predetermined threshold Q (0) (NO in S118), the electric power
electrically charged to capacitor 900 is electrically discharged to
battery 700 in preparation for the occurrence of the reverse
(S120). The electric power electrically charged to capacitor 900 is
electrically discharged to battery 700 (NO in S118, S120) until
amount Q of capacitor electric energy becomes lower than
predetermined threshold Q (0) (YES in S118).
[0084] Thus, it is possible to turn capacitor 900 into the
electrically chargeable state without any waste of the electric
power electrically charged to capacitor 900 before the reverse of
the vehicle. In this way, the electric power generated in MG (1)
200 and MG (2) 300 during the reverse can be electrically charged
to both of battery 700 and capacitor 900. Therefore, the greater
suppressing torque can be generated in comparison with a case of
the electric charging only by battery 700, as indicated by a solid
line in FIG. 6, thereby suppressing the reverse of the vehicle.
[0085] Additionally, amount Q of capacitor electric energy becomes
substantially zero at predetermined threshold Q (0). Therefore, the
larger electric power can be electrically charged by capacitor 900
by decreasing amount Q of capacitor electric energy down to
substantially zero before the reverse.
[0086] As described above, in the drive device according to the
present embodiment, the capacitor can be turned into the
electrically chargeable state by decreasing the electric power
electrically charged to the capacitor in a case where the reverse
of the vehicle is estimated. Therefore, the electric power
generated in the MG (1) and the MG (2) can be electrically charged
to both of the battery and the capacitor during the reverse.
Therefore, the greater reverse suppressing torque can be generated
in comparison with a case of the electric charging only by the
battery, thereby suppressing the reverse of the vehicle.
[0087] It is to be understood that the embodiment described herein
should be illustrative but not limitative at all points. It is to
be intended that the scope of the present invention should fall
under not the above-described embodiment but claims, and should
further encompass all variations within significance and range
equivalent to the claims.
* * * * *